Extensive research on the functional role of the monkey's prefrontal cortex has led to the designation of cortex in its principal sulcus as the neural substrate for spatial memory. However, more recent research has indicated the role of this prefrontal segment in the organization of visually guided or visually cued instrumental responses. Certain of its functional properties appear similar to those found for the inferior parietal lobule. The proposed research will assess the functions of principalis cortex, and its relationship to the parietal areas, in the programming of oculomotor and skeletomotor acts. Recordings will be obtained for single unit discharges from these areas during the monkey's performance on a sequence of complex tasks. The relevant units will be identified by antidromic stimulation from efferent structures. The findings are expected to provide information with regard to the coding properties of prefrontal units and the functional neuronal organization in task performance.